1. Field of the Invention
The invention relates to a suspension assembly for suspending a gypsum board panel from a support structure, to a combination of the suspension assembly with a gypsum board panel, and to a non-load bearing partition wall utilizing these components.
2. Description of the Prior Art
In recent years, removable partition walls have been widely used in buildings. In general these walls involve mounting channel-like runners on the floor and ceiling, installing vertical, channel-like studs in laterally spaced relationship between the runners, and securing gypsum board or the like panels to the studs. The panels can be screwed or glued to the studs to provide a sturdy wall. However, this technique is labor intensive. It involves having to fill and tape the joints and conceal them with battens in order to produce a neat, finished appearance.
A battenless system has been developed which is described in U.S. Pat. No. 3,550,338 issued to Satkin et al. This system involves securing long metal strips with adhesive to the back of a gypsum board panel. The strips are located along each vertical side edge. Hooks protrude rearwardly from each strip. These hooks engage cut-outs in the side leg of the adjacent metal channel stud. Each hook has a cam surface, which coacts with the side edges of the cut-out to draw the panel tightly against the stud as the panel is lowered into place. The hooks suspend the panel a short distance above the floor so that the panel weight acts to hold it in place.
The metal strips which are used in this prior system must be of substantial length and width. This requirement arises from a characteristic of gypsum board panel that the bond between the board filling and the paper layer is frequently weaker in certain portions of the panel than in others. By providing long, wide strips, at least portions of each strip will be attached to properly bonded material. One disadvantage in using such strips is that they are relatively expensive and thus contribute significantly to the cost of the system.
The metal strips, hooks and stud cut-outs of this prior system must be precisely manufactured and positioned. This is done so that they match perfectly and draw adjacent panels into closely abutting relation. The resulting joint is, under this circumstance, a line and not an unsightly gap. This precise manufacturing also contributes to the cost of the system.
Another limitation of this type of system is that considerable stress due to the weight of the panels is placed on a narrow section of the stud. This leads to sagging and weakening of the lateral stability of the wall. Reinforcing to overcome this problem is usually not added because of the increased cost.
With a view to overcoming the limitations of this type of system we have devised a system in which gypsum board panels are suspended from horizontal channel members by a number of suspension assemblies comprising gang nail plates affixed to the rear face of each panel and carrying a hanger member having a lower inclined or cam portion which co-operates with a side leg of the horizontal channel member to draw the panel firmly against an adjacent vertical stud member. By suspending the panels from horizontal channel members, it is possible to use panels having loose tolerances in their dimensions and to shift the panels laterally along the horizontal channel members to achieve a close abutment and what may be termed line joints. This system is disclosed in our Canadian Pat. No. 1,002,279 issued on Dec. 28, 1976.
As disclosed in our Canadian Pat. No. 1,002,279 each gang nail plate comprises a plate having a plurality of integral, panel-piercing, non-threaded tangs projecting from the plate. The gang nail plates are attached to the panel simply by placing each plate on the back of the panel and driving the plate against the panel so that the tangs pierce the panel to a substantial depth, but without protruding from the front face thereof. The gang nail plates are relatively inexpensive and are easily attached to the back of the panel using simple mechanical means.
In the suspension assemblies of our previously proposed system, the cam portion of the hanger member projects downwardly beyond the bottom edge of the plate. While this configuration has been found to work satisfactorily with dense gypsum board panels, such as Western Canadian gypsum panels, the plate is not always effective when applied to gypsum board panels, such as Eastern Canadian gypsum panels, which are considerably less dense due to the use of a different raw gypsum material. More particularly, when the plate is applied to less dense gypsum panels, it has been found that under the loads which arise during assembly and use of the system, the hanger member tends to lever on the bottom edge of the plate and causes the plate to pivot around its upper edge. As a result of this action, the tangs at the lower end portion of the plate are drawn out of the board, and under certain circumstances, this may cause the entire plate to twist out of the board.
An object of the invention is to provide a suspension assembly which overcomes the above disadvantages.